author | William Roberts <williamr@symbian.org> |
Tue, 16 Mar 2010 16:12:26 +0000 | |
branch | Symbian2 |
changeset 2 | 2fe1408b6811 |
permissions | -rw-r--r-- |
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// ------------------------------------- |
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// lowest_bit.hpp |
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// |
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// Position of the lowest bit 'on' |
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// |
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// (C) Copyright Gennaro Prota 2003 - 2004. |
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// |
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// Distributed under the Boost Software License, Version 1.0. |
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// (See accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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// |
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// ------------------------------------------------------ |
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|
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#ifndef BOOST_LOWEST_BIT_HPP_GP_20030301 |
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#define BOOST_LOWEST_BIT_HPP_GP_20030301 |
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#include <cassert> |
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#include "boost/pending/integer_log2.hpp" |
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namespace boost { |
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template <typename T> |
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int lowest_bit(T x) { |
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assert(x >= 1); // PRE |
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// clear all bits on except the rightmost one, |
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// then calculate the logarithm base 2 |
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// |
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return boost::integer_log2<T>( x - ( x & (x-1) ) ); |
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} |
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} |
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#endif // include guard |